Hi
I had a custom made Linux machine running a Time Table processor. The HDD (IDE) failed and I replaced it with a SATA. Ran the recovery disk supplied by the installer and I am getting a kernel panic “VFS: Cannot open root device “LABEL =/ or 00:00. Please append a correct “root= boot option. Kernel panic : Unable to mount root fs on 00:00
Looking into etc/fstab there is nothing (empty)
Please help

What type controller(s) was/were/are connected to old and new disks? Disk device drivers may not have been the same for both in your PC, which could cause the required disk driver for the replacement to be absent from the initrd that enables boot success. Using the recovery disk you probably needed to chroot into the installed system and regenerate the initrd. More specifics would require you provide machine and distro information. Running inxi -dSa and lspci from a rescue boot and naming installed distro and version should be able to provide that information. Also, /etc/fstab on the installed system simply cannot be empty and expect an operable system. What do you mean by "etc/fstab there is nothing (empty)"?

Maybe looking at the recovery disks fstab ?.

VFS is a layer in the kernel - might imply that the initrd has actually run. Initrd will probably still need updating regardless.